From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1pKEU0-00065z-03 for mharc-grub-devel@gnu.org; Tue, 24 Jan 2023 03:16:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pKETr-00065b-Ll for grub-devel@gnu.org; Tue, 24 Jan 2023 03:16:39 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pKETp-0005dt-Um for grub-devel@gnu.org; Tue, 24 Jan 2023 03:16:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674548192; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KhhTDNao4Vd+W3QaATJe5hG4y/pykhEuDBuWnoZ+Mxo=; b=JzETiNJTw+EPIqeUaFMulSUPUd1/bwagtwgDWTRf0P1PldMjWeaXbdJED42wCj3n3me29u yzOE4UKKk8d92djIF2hgrEcI00TCfNY/Nrs8f0rMIAtRAuxVyTQjOXJ9UUQ+vtSygyX9ii AIf1Adc635V9Njp//cGqaT7tTQR6axo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-605-BWPfETnkNWmIddVKgH8dIg-1; Tue, 24 Jan 2023 03:16:28 -0500 X-MC-Unique: BWPfETnkNWmIddVKgH8dIg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3CAEF80D119; Tue, 24 Jan 2023 08:16:28 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.192.186]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 124E22026D4B; Tue, 24 Jan 2023 08:16:28 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id AA8C3180060E; Tue, 24 Jan 2023 09:16:26 +0100 (CET) Date: Tue, 24 Jan 2023 09:16:26 +0100 From: Gerd Hoffmann To: Glenn Washburn Cc: The development of GNU GRUB , Daniel Kiper Subject: Re: [PATCH] grub-shell: Add flexibility in QEMU firmware handling Message-ID: <20230124081626.a34tvlfivkc6mpoi@sirius.home.kraxel.org> References: <20230121061520.1619840-1-development@efficientek.com> <20230123092809.sycmpu4iu5hn6b6n@sirius.home.kraxel.org> <20230123140947.7998a115@crass-HP-ZBook-15-G2> MIME-Version: 1.0 In-Reply-To: <20230123140947.7998a115@crass-HP-ZBook-15-G2> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Jan 2023 08:16:40 -0000 Hi, > > > Do not load the system 32-bit ARM firmware VARS file because it > > > must be writable to prevent a data exception and boot failure. So > > > in order to use the VARS file, it must be copied to a writable > > > location, but its quite large at 64M and is not needed to boot > > > successfully. > > > > You can load the VARS file with snapshot=on (and drop readonly=on) to > > make things work without copying the file. > > Good to know. Do you know of any benefit to doing this (ie. using the > installed VARS file)? Well, the firmware expects it can write to VARS flash. ovmf has for historical reasons code to cope with non-flash or readonly VARS (so -bios works), but armvirt has not. Which is why you see the failures. snapshot=on allows the guest write to a in-RAM throwaway snapshot, which is the same as using a writable temporary copy of the vars file, but without the need for a temporary file. take care, Gerd